It has become increasingly necessary in conveyor installations to provide flexibility, that is, adaptability of the conveyor to changing conditions. The concept of conveyors as being solely a transporting device has long been displaced by the concept that the conveyor is a means of tying together a number of different functions, various ones of which require the articles to be temporarily displaced from the conveyor so that some type of operation may be performed on them. The concept of initially designing the conveyor so that it provides a permanent layout for the performance of these functions has been replaced by the recognition of the need for adaptability to conveyor usage. To this end, provision for permanent or temporary removal of articles from the conveyor at various points along its length needs to be changed from time to time. In the past, this has involved substantial time and expense because the adaptation of the conveyor from one operation to another involved substantial labor. The increasing cost of labor coupled with the increasing frequency of such changes indicates the desirability of making such changes as simple as possible.